Fan



y 9, 1962 o. D. TWIST 3,036,642

FAN

Filed" March 26, 1957 bk 2A III I N VEN TOR.

Sttes Filed Mar. 26, 1957, Ser. No. 648,593 2 Claims. (Cl. 170-159) My invention relates to a fan of parts which may be readily assembled and attachable to a motor for use.

It is among the objects of my invention to provide a fan adapted to be readily assembled and attached to a motor for use.

A further object of my invention is to provide such a fan which is economical in manufacture and use and which may be easily understood and used by the average user. My invention is particularly designed for safety and provides a fan using blades of fiberglass or other suitable material. My invention also comprises such other objects, advantages and capabilities as will later more fully appear and which are inherently possessed by my invention.

While I have shown in the accompanying drawings preferred embodiments of my invention, yet it is to be understood that the same are susceptible of modification and change without departing from the spirit of my invention.

Referring to the drawings, FIG. 1 is a front elevational view of my fan blade and hub; FIG. 2 is a side elevational view of the same; FIG. 3 is a bottom face view of the hub; FIG. 4 is a front elevational view of one blade and FIG. 5 is an end elevational view on line 5-5 of FIG. 1.

The embodiment selected to illustrate my invention comprises a hub 10, preferably formed of aluminum having a base plate of body portion 11 preferably round in contour with a central hollow nipple 12. Blade 13 has a reduced rounded inner end 14 positioned against the front of base plate 11. Another blade 15 has its reduced rounded inner end 16 positioned on end 14 of blade 13. Said blades 13 and 15 are attached by spaced screws 17 extending therethrough and through screw threaded openings in base plate 1 1 where they are held in place by nuts 18 threaded on screws 16 and bearing against the back of base plate 1-1.

Looking at blade 13 from the front, as in FIG. 1, blade 13 extends outwardly from inner end 14 along substantially a straight line to form leading edge 19. It then curves outwardly downwardly and then inwardly with outer curve 20 to form inner trailing edge 21. The leading portion 23 of blade 13 which is inward from its leading edge 19 to substantially the center of the blade is substantially flat and on the same plane as the front of base plate 11. The trailing portion 24 of blade 13 is curved from substantially the center of blade 13 to its trailing edge .21. The curved portion is concave at its suction surface.

Blade 15 has the same portions as blade 13. When blade 13 is in the position shown in FIG. 1, its leading edge is at the top, and the corresponding leading edge of blade 15 is at the bottom, but in half a revolution of hub 10, the positions are reversed.

In use my device is readily attachable to an electric motor or any suitable supply of force by extending the nipple 12 into the shaft of the motor or the like and attaching the same by tightening screw 25 against the shaft of the motor or the like.

I use blades made of fiberglass which consist of a combination of 25% fiberglass and 75% resin. This material is rigid to move the air or atmosphere.

The thinness of my blades is important for efiicient operation, and I prefer blades of the thickness of A of an inch. More air is moved with less power. This is drastically different in that the leading 'half of the blade BAlBfifi lZ Patented May 29, 1962 moves no air other than knifing or precutting and acts as a support for the propelling surface of the fan blade.

By reversing the attachment of blades 13 and 15 as set forth on hub 10, the blades will operate for a reverse flow of air for air intake, when attached to a motor properly rearranged.

Where my blades are of fiberglass, greater safety is provided, because contact or obstruction with the blades will cause them to shear or break off with substantially no injury to the object contacted. The blades being of such material are inexpensive, easily available and may be readily and economically replaced.

My fiberglass blades provide a reduction of substantially of the weight of the ordinary metal blades. Fiberglass is approximately one quarter the weight of steel per cubic inch. Greater acceleration and the saving of motor power is at once apparent with the use of my fiberglass fan.

The inherent construction of my fiberglass blades permits the dilating of the tips or outer portions of these blades under pressure and their return to normal position when the pressure has been discontinued.

When my blades are in action, my fan employs a different principle of leverage to move the air, involving three factors: (1) the density of the air against the propelling surface builds up, creating a. partial vacuum on the opposite or front side of the fan which causes part of the pitch to decrease at the extremities of the blade, decreasing inwardly so that blade has equal propelling power from center of rotation outward; (2) simultaneously the outer ends of the blades move forward, toward the direction of air intake, causing the fan to assume a concave shape, which i visible when the fan is viewed at right angles to its axis and which actually causes the blades to lean away from the center of rotation and (3) since the air must follow the line of least resistance it moves towards the center of rotation, or down the slanted blades. End-throw of air is practically eliminated.

My fan also definitely removes radiator block.

Having thus described my invention, I claim:

1. A fan comprising a hub, a plurality of fiberglass blades, said fiberglass consisting of a combination of 25% fiberglass and 75% resin, each blade having a flat re duced inner end portion, said blades attached to said hub at their flat reduced inner end portions, each blade having a leading edge, a substantially flat portion on the same plane as the flat reduced inner end portion extending from the leading edge to substantially the center of the blade, a'trailing edge and a curved portion extending from substantially the center of the blade to the trailing edge, said curved portion being concave at its suction surface, each of said blades having an outer tip, said outer tips adapted to advance under pressure of centrifugal force and air when said blades are rotated causing air to move toward the center of rotation for increased acceleration of said blades, said outer tips adapted to return to normal position when rotation has been discontinued or so reduced as to release pressure.

2. A fan comprising a hub, a plurality of thin fiberglass blades, said fiberglass consisting of a combination of 25% fiberglass and 75% resin, each blade having a fiat reduced inner end portion, said blades: attached to said hub at their fiat reduced inner end portions, each blade having a leading edge, a substantially flat portion on the same plane as the flat reduced inner end portion extending from the leading edge to substantially the center of the blade, a trailing edge and a curved portion extending from substantially the center of the blade to the trailing edge, said curved portion being concave at its suction surface, each of said blades having a curved reduced outer tip, said outer tips adapted to advance under pressure of centrifugal force and air when said blades are rotated causing air to move toward the center of rotation for increased acceleration of said blades, said outer tips adapted to return to normal position when rotation has been discontinued or so reduced as to release pressure, said blades being of fiberglass adapted upon contacting a foreign object during rotation to break off Without substantial injury to the foreign object.

1,096,079 Viall May 12, 1914 4 Rosen Dec. 29, Ferreby Apr. 12, Samueis Oct. 5, Gant Sept. 18, McLean Dec. 11, Perkins Nov. 16, Alex Oct. 11, Rofiy July 10, Moeller Feb. 12, Simon et a1. Dec. 27, 

